The Pelican Puzzle | Thursday, 24 November 2022
This story originally ran in our September issue. To receive our Australian BirdLife magazine, become a member today.
Before the noise or the sheer numbers, it’s the smell that hits you. The distinctive aroma of tens of thousands of fish-eating pelicans—of wet feathers and guano and rotting fish leftovers—is a smell that sears its way into your memory. But it’s the spectacle of it all that stays with your forever, and the privilege of witnessing this festival of new life. There is nothing else quite like it: tens of thousands of pelicans, all crowded together on the shores of Lake Brewster in what is one of the largest breeding events at Lake Brewster, and for the regulated Murray–Darling Basin, in recent decades.
But where did they all come from?
The Lake Brewster pelican colony, NSW. Photographed by: Mal Carnegie, Lake Cowal Foundation
Like many waterbirds, pelicans breed in boom-and-bust cycles according to environmental conditions—after heavy rain, they’re known to flock in their thousands to breed in huge colonies on islands and secluded shores. After two consecutive wet years fuelled by La Niña, Lake Brewster was filled with water, and the pelicans followed suit. But how they know to come inland to breed during flood events remains a mystery.
The lake, part of the Lachlan River catchment in the Central West of NSW, was already an important site for pelicans—one of the few sites in the Murray–Darling Basin where pelicans are known to breed consistently in large numbers (more than 6,000 nests). But this time, conditions were perfect, and the numbers were looking like they were going to be big. While most nesting events number between a few hundred and a few thousand birds, environmental water managers estimated more than 15,000 nests at the peak. To put the significance of this breeding event at Lake Brewster into perspective, historical breeding events from 1984–85 to 2016–17 were estimated at between 1,250 to 6,100 nests.
Once they hatch, a single pelican chick (affectionately known as a ‘pinkie’) can eat between 300 grams and almost a kilogram of food per day as they grow, and adults eat nearly two kilograms—at its peak, this colony alone consumed a staggering 15–30 tonnes of fish, mostly carp, every day.
Sadly, pelicans, like other waterbirds, are facing growing threats—from habitat loss, consequences of human development (collisions with powerlines, vehicles, fishing line entanglement), overfishing, pollution and changes in water flow regimes. And with increasingly frequent and prolonged droughts making suitable breeding conditions increasingly scarce, major breeding events such as these are key to helping boost the pelican population, although we won’t know their impact for years to come.
But after the boom comes the bust. While the majority of the 30,000 plus Brewster colony bred under such ideal conditions, there was a cohort of later breeders who faced more challenging conditions. Weather-related events, feral animal predation, disease and food constraints are thought to be amongst the primary factors lowering reproductive success in colonial birds such as the Australian pelican. And fish stocks can’t last forever when they’re consumed this quickly. After the months-long feeding frenzy, the mortality rate can increase, and weak and hungry birds are left behind as the rest of the colony head inland or towards the coast as summer ends. And once more, we are left with more questions than answers.
As for the biggest question of all—the impacts of climate change, and what kind of effect a drying climate and increased frequency of severe weather events may have on these boom-and-bust events—only time will tell.
Despite being one of Australia’s most iconic waterbirds, there’s a lot we don’t know about pelicans. Their movements have long baffled pelican enthusiasts. Where do they come from? Where do they go? Do they return to where they hatched?
We can’t protect what we don’t know, which is why a dedicated network of like-minded people from community volunteers, scientists and environmental water managers are now determined to answer these questions—tracking the movements of pelicans through dedicated banding projects across Australia. Lake Brewster is always closed to the public, but accessible to those with an active role in the management and protection of the wetlands ecosystem including the pelican colony.
The question of natal site fidelity—an animal’s tendency to return to its place of birth—is one researchers at Lake Brewster are especially keen to answer. If pelicans show strong natal site fidelity, it means there are limited options for new nesting sites—making the protection and management of existing sites critical to their conservation.
This year alone, researchers banded 245 young pelicans with uniquely numbered and easily identifiable orange leg bands at the lake. This joint project between NSW Department of Environment and Planning (DPE), Lake Cowal Foundation, University of NSW and WaterNSW is tracking how far the birds travel and whether they’ll revisit Lake Brewster or other wetlands over the next 10–15 years—or however long the bands stay on!
BirdLife Australia’s own East Gippsland Conservation Coordinator, Deb Sullivan, was on site at Lake Brewster banding young with other researchers, and it was an experience she will never forget.
“It was a once in a lifetime opportunity—it was just brilliant,” she says. “But it’s hard to comprehend the numbers as well. You just cannot take in the scale of it all because you can only see so far.”
Far from the inland floodplains of Central NSW, there lies another vital breeding stronghold for Australia’s pelicans.
Today, the Gippsland Lakes is one of only two permanent sites in Victoria, when there were once 11 breeding sites across the state. Coastal colonies like these dispel the myth that pelicans only breed inland—here, pelicans also enjoyed an extended breeding season after the rains, revealing that even coastal populations are highly rainfall-dependent.
It’s here that Deb coordinates BirdLife Australia’s annual Great Pelican Count, a citizen-science project that’s tracking the population, movements and health of these remarkable birds in Victoria’s east. Supported by the East and West Gippsland Catchment Management Authorities, this year’s count saw almost 100 participants gather on a cloudless April day across 77 locations. Citizen scientists recorded a staggering 1,135 pelicans—almost double the tallies from the 2021 and 2019 counts.
The data collected through just 30 minutes of counting provides a snapshot of pelican behaviours and population dynamics, while contributing to Deb’s ongoing pelican monitoring and conservation project at the Lakes. Between counts, Deb can track local pelicans in real-time using satellite transmitters fitted to the birds, and is hoping to deploy 10 more tracking devices on adult and juvenile birds soon.
“It’s not only interesting to know where pelicans go,” says Deb, “but it helps us understand their behaviour better, the habitats they like to use, and improves management practices for the future of the species.”
Deb is one of a handful of pelican researchers scattered around Australia as part of three banding projects: one based in Lake Brewster and at the Gayini Wetlands in the southern Murray–Darling Basin, and another study group situated in Victoria’s Westernport and Port Phillip Bays. Each have band colours unique to their project, and each is slowly piecing together the great pelican puzzle.
At this stage, each team is working independently to answer the same research questions about pelicans and their movements, but in future, they’ll share their findings to paint a nation-wide picture of how our pelican population is faring, including the threats they’re facing.
Meanwhile, sightings of their banded birds are revealing the astonishing distances these mighty travellers can cover, with the furthest confirmed sighting of a Lake Brewster bird turning up over a thousand kilometres away near Noosa, and one of Deb’s own birds spotted as far as Brisbane.
As for this far-flung traveller?
“It’s super exciting,” Deb says. “Anything that you get beyond the region of where you’re working is very exciting, and that’s why it’s so important we have citizen scientists looking out for banded birds.”
“Pelicans are found along our coastlines and everyone knows them, so they’re a great entry-level species for people of any age who might be curious about citizen science. The citizen scientists are paramount for us, across all our projects—they are our tracking devices. So please, keep an eye out for any banded pelicans, wherever you may be!”
The next time you see a pelican, check to see if it’s wearing a coloured leg band. Each report of a banded bird is another piece of the pelican puzzle, and helps us better understand and protect these Australian icons.
If you see a pelican with a coloured leg band, please contact:
E: firstname.lastname@example.org, email@example.com and firstname.lastname@example.org.
Don’t forget to include:
If you find a coloured leg band without a bird, please report it too!
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